I have read that newborn babies have an inherent sense of 2, or 3 or sometimes 4 objects. Various experiments using attention span suggest that this is true. I can provide a ref if there is interest. It's in a new 2002 book on where math comes from.

My view is that the number ability of babies is unconscious and quantum mechanical. It is reasonably unconscious as newborns barely have consciousness. That it is quantum mechanical is hypothesis. A further hypothesis is that the quantum mechanical medium in which the number of objects are sensed is not what is now considered to be physical. I suggest this based on the fact that a newborns brain is insufficiently developed physically to sense numbers, and I do not think it happens by instinct. That is, it does not come from our genes. But that is a guess.

What prompts me to write this now is that I just had an experience of unconscious number sensing.
I had come to this library to send 2 emails. After sending the 2 emails, I had the intuitive feeling that I had not finished all that I had come to do.

In sitting back and thinking back on my original intentions, what came to me was the number 2. I was able to sense 2 essentially invisible objects in my brain, and I had a strong sense that the number was stored in something unconscious. Only by thinking back on what the actual emails were was I able to determine that I had completed my intentions.

In realizing this process, I am benefitted by my extremely poor short term memory. Anyone with a decent memory would remember exactly what his or her intentions were and not have to rely on the unconscious for recall. So I expect that this is not a common experience.

But in a way, number sense of this sort must be close to reality as babies do it before being brainwashed and developing filters for all input data. It seems to be an ability that is not lost, in spite of the filters.